Question

A black body emits radiation of maximum intensity of wavelength '\(λ\)' at temperature 'T' K. Its corresponding wavelength at temperature \((2.5T)\) K will be

• A. \(\frac{2λ}{3}\)
• B. \(\frac{2λ}{5}\)
• C. \(\frac{4λ}{5}\)
• D. \(\frac{16λ}{81}\)

Hint:

Thermal resistance is L over K A, so equal area and resistance make L proportional to K.

Answer 1

The Correct Option is B

Step 1: Intuition:
A better conductor needs a longer rod to give the same resistance to heat flow.

Step 2: Result:
Since $K_1:K_2 = 6:5$, the lengths follow the same ratio, 6:5 (B).

Final Answer:
6:5. \[ \boxed{6:5} \]